Centrifugal air compressor control device



y 13, 1958 M. KADoscH' ETAL 2,834,534

CENTRIFUGAL AIR COMPRESSOR CONT'ROL DEVICE Filed Sept. 22, 1952 ,fl |||||||||||||||||\u\ United States Patent '0 CENTRIFUGAL AIR COMPRESSOR CONTROL DEVICE.

Marcel Kadosch, Paris, and Jean Le Foll, Le Pre-Saint- Gervais, France, assignors to Societe Nationale dEtude et de Construction de Moteurs dAviation, Paris, France, a company of France Application September 22, 1952, Serial No. 310,870

Claims priority, application France September 27, 1951 Claims. chm-114 The present invention relates to a device for the regulation and control of a flow by means of which it is possible to regulate or modify a rotational movement imparted to this flow in a chamber of round form.

This device comprises an adjustable obstacle arranged on a Wall against which the flow to be controlled takes place.

The obstacle may be a solid obstacle which is preferably made movable, so that it can be set in operation when required. It may also preferably be a fluid obstacle consisting of an auxiliary jet leaving through an oriented hole or slot so as to impart to this auxiliary jet a velocity component perpendicular to the velocity component of the flow to be controlled.

The principle of the deflection of a flow of fluid by means of a solid or fluid obstacle has already been described in the U. S. Patent No. 2,702,986, filed on August 5, 1949, and patent application Ser. No. 221,551, filed on April 18, 1951, by Marcel Kadosch, Frangzois G. Paris, Jean Bertain and Raymond H. "Marchal, now Patent No. 2,793,493.

The present invention concerns a novel application of this principle.

The invention may be employed to great advantage in compressors for the purpose of replacing the movable blade lattices which are disposed in some apparatus of this type before the inlet into the rotor in order to regulate the circulation and thus to vary the delivery pressure.

The prescription which follows with reference to the acompanying drawings, which are given by way of nonlimitative example, will enable the manner in which the invention can be carried into effect to be readily understood.

Figures 1 to 3 illustrate the application of the invention to a centrifugal compressor comprising an axial flow inlet rotor, the said figures corresponding to three differ ent regulations.

Figure 4 shows on a larger scale a part of Figure 1.

In Figures 1 to 3 there is diagrammatically shown a centrifugal compressor in which the magnitude of the flow and its direction at the inlet of the rotor are regulated. In some known compressors, a ring of fixed but orientable blades is disposed in the admission volute for this purpose.

In the drawings, the admission volute 6 has an inlet aperture at 7 in a plane parallel to the axis of the rotor which is projected at 8. There will be seen at 9 the axial flow inlet rotor, to the rear of which there is situated the centrifugal rotor surrounded by the diffuser and the outlet volute, 10, having its orifice at 11. The orientable ring of blades, which is normally situated in the admission volute 6, around the inlet rotor 9, is dispensed with, and is replaced in accordance with the invention by a ring of small hollow elements 12 situated at a certain distance apart and suitably profiled to cause the air drawn into the inlet rotor 9 and obliged to pass between these elements (arrows f) to undergo the 2,834,534 Patented May 13, 1958 2 minimum resistance. These elements 12 may be, for example, cylinders of oval section extending between the flanges of the admission volute 6 (parallel to the plane of the drawing). Each element has two inwardly facing convex wall portions (see Fig. 4).

Each of the elements 12 is divided by a partition 14 into two compartments 12a and 12b, each of which is formed with a slot 15a, 15b oriented obliquely towards the inlet of the rotor 9. All the compartments 12a of the elements 12 may be fed with air under pressure through a circular duct 160, while similarly all the compartments 12b may be fed under pressure through a circular duct 16b. In the example illustrated, the air is taken through a pipe 17 from the outlet volute 10 and may be passed through a cock 18 either towards the circular duct 16a (Figure 1) or towards the circular ducts 16b (Figure 2). The cock 18 may also occupy a third position, in which neither of these ducts is fed (Figure 3).

In the position of the cock illustrated in Figure 3, for example, the air under pressure passing through the duct 16:: to the compartments 12a escapes through the slots 15a which direct it obliquely as indicated by the arrows f towards the convex wall portion of the next element 12. Consequently, the air drawn through the compressor into the volute 6 and passing into the gaps between the bodies 12 is deflected as indicated by the arrows f. This air is thus given a rotation component in the opposite direction to the rotation of the rotor of the compressor, indicated by the arrow f The maximum delivery pressure is. thus obtained.

If the cock 18 is so positioned that the duct 16b is fed (Figure 2), the air will leave the compartments 12b through the slots oriented in the opposite direction to the slots 15a, i. e. towards the convex wall portion of the next element 12, and the air drawn in by the rotor of the compressor will then be given a rotation component in the same direction as the rotation of the rotor. The minimum delivery pressure will be obtained. If the cock,18 is then so positioned that none of the ducts 16a, 16b is fed (Figure 3), the air will not undergo any deflection in its passage between the hollow elements 12. The admission into the rotor 9 will be axial and a mean delivery pressure will be obtained.

It will be understood that the device described permits ofproviding a considerable mechanical simplification of variable-circulation compressors due to the elimination of the orientable blades and of the control means therefor.

We claim:

1. In a centrifugal air compressor having a rotor provided with radial blades, a discharge pressure control device comprising a plurality of arcuately spaced, air inlet passages extending radially of, positioned around, and ending at the intake portion of said rotor whereby air is normally sucked through said passages and into said intake portion in a radial direction with respect thereto, and controllable means positioned laterally of said passages for selectively diverting the air flows therethrough from said radial direction.

2. In a centrifugal air compressor having a rotor provided with radial blades, a discharge pressure control device comprising a plurality of arcuately spaced, air inlet passages extending generally radially and distributed around the intake portion of said rotor whereby air is normally sucked in through said passages in a general radial direction with respect to said rotor, and controllable means positioned laterally of said passages for diverting the air flows therethrough from said radial direction, selectively in a direction opposite to the peripheral velocity of the rotor blades and in the same direction as said peripheral velocity.

3. Device as claimed in claim 2, wherein each air inlet passage is bounded by two smoothly curved, convex walls, the diverting means being positioned on each wall and being substantially opposite each other.

4. Device as claimed in claim 3, wherein thedivertihg means comprise a jet forming nozzle facing in a generally transverse direction with respect to the corresponding air inlet passage whereby the jet formed by a nozzle exerts a diverting action on the air flow through said passage and urges the same into adhering contact with the opposite convex wall. i

5. Device as claimed in claim 4, wherein all the jet forming nozzles-facing in the same direction relatively to the peripheral velocity of the rotor are simultaneously and exclusively activatable.

References Cited in the file of this patent UNITED STATES'PATENTS 819,273 Guy May 1, 1906 4 Stalker Dec. 15, Stalker Mar. 16, Sammons et'al. June 21, Price Nov. 8, Brown Aug. 21, Melchior May 20, Clark Jan. 13, Kadosch et al Mar. 1,

FOREIGN PATENTS Austria Apr. 15, Great Britain June 3, Italy H-. Apr. 6, Great Britain Feb. 24, Belgium May 31, Great Britain Apr. 30, Germany L Mar. 7, France Dec. 12, France 'Mar'. 7, 

